Circuit breaker



y 1930- I c. D. BURROWS 1,768,885

C IRCUIT BREAKER Filed Feb. 19, 1927 3 Sheets-Sheet l WITNESSES:INVENTOR C/arence 0 BU/l'Oh/J.

July 1, 1930. c. D. BURROWS CIRCUIT BREAKER Filed Feb. 19. 1927 3Sheets-Sheen 2 INVENTOR C/arence [1B urron/J.

' AfTORNEY Patented July 1, 193i UNITED STATES PATENT OFFICE CLARENCE D.BURBOWS, OF PEOBIA, ILLINOIS, ASSIGNOIB, TO WESTINGHOUSE ELEC 'I'RIC &MANUFACTURING COKPANY, A CORPORATION OF PENNSYLVANIA CIRCUIT BREAKERApplication filed February 19, 1927. Serial No- 189,667.

M invention relates to circuit breakers and particularly to circuitbreakers for controlling current supplied to small motors and domesticappliances.

One object of m invention is to provide a circuit breaker o thetumbler-swltch type wherein the switch is moved to open position inresponse to overload or short-circuit conditions.

Another object of my invention is to provide a circuit breaker of thetumbler-switch type wherein the switch blade is normally biased towardopen position by a spring that is re-wound when the switch is moved toclosed position, and wherein the switch is operated to open or closedpositions with a snap action, by means of an over-center spring that isconnected to the operating handle and to a clutch releasably connectedto the switch, and wherein the clutch is actuated in response topredetermined current conditions.

Another object of my invention is to provide a circuit breaker of thetumbler-switch type having the above noted characteristics and whereincalibrating means are provided for varying the power required to operatethe clutch, whereby the switch may caused to open in response topredetermined current conditions.

A further object of my invention is to provide a circuit breaker of thetumbler-switch type that is trip-free of the operating handle andwherein the circuit breaker will open in response to predeterminedcurrent conditions, regardless of the position of the operating handle.

These and other objects of my invention that will be made apparentthroughout the further description thereof are attained by means of thecircuit-breaker apparatus hereinafter described and illustrated in theaccompanying drawings wherein Figure 1 is an exploded view, inperspective, of various parts of the circuit-breaker mechanism.

Fi 2 is a transverse section through the circuit-breaker housing,showing the circuit breaker in end elevation.

Fig. 3 is a transverse section of the hous ing, showin the opposite endof the circuit breaker in e evation.

Fig. 4 is a longitudinal section of the housing, showlng the circuitbreaker in the side elevation.

5 is a view, partially in longitudinal section and partially inelevation, of the c'ircu1t breaker shown in Figures 2, 3, and 4.

Fig. 6 is a transverse section of the clutch mechanism taken on the lineVI-VI of Fig. 5.

eferring to the drawin s, the ci.cuit breaker comprises a housing madeof porcelain, molded composition or any suitable insulating material andadapted to contain the circuit-breaker apparatus. The circuitbreakerapparatus is mounted upon a sheetmetal supportlng frame 8 of U-shapethat is secured to the bottom of the housing by means of screws 9.

Referrin particularly to Fig. 1, the switch-bla e member'll is mountedupon, and adjacent to the end of a hollow shaft 12 and oscillatesbetween open and closed positions. When the switch is in closedposition, it enga es contact members 13 and 14. The shaft an switch arenormally biased toward the open position, indicated by dotted lines inFig. 1, b means of a helical spring 15 that is woun about the shaft andhas one end connected thereto and the otherend connected to a supportingframe 8. The spring is rewound when the switch is moved to the closedposition shown in Figs. 1 and 2, wherein the switch member 11 is inengagement with the contact members 13 and 14.

An operating handle 16 is rotatably mounted upon the shaft 12 and isprovided with an openlng 20 for receiving a yoke member 17 thatconstitutes a portion of a clutch mechanism to be hereinafter described.The clutch yoke 17 is ofU-shape and the end portions 18 and 19 thereofare rotatably mounted in bearings 10 in the supporting frame 8 and alsoserves as bearings for the shaft 12 which extends through the ends ofthe yoke. The end portion 18 is provided with a pair of oppositelydisposed notches 21 for receiving clutch pins 22 that are feathered inlongitudinal notches 23 in the end of the shaft 12.

.operating handle. yoke is limited by the stop members 35 and 736 formedintegrally with the supporting The clutch pins 22 are carried by acollar 22A that is threaded upon an adjusting rod 24 which extendsthrough the hollow shaft 12. A secondary clutch collar 25 cooperateswith the collar 22--A and serves to lock the collar 22A in adjustedposition upon the rod 24 and also serves to provide an annular groove 26for receiving a shifting bar 27. The bar 27 is pivoted upon a'shaft 28provided with an armature 29 which is actuated by an electromagnet 31that is connected in series with the switch contacts 13 and 14, and issupported upon plates 40 attached to the frame 8. g

The operating handle 16 is provided with a pin 32 upon which a guide rod33 is pivoted, the latter extending through an opening 30 in the yoke17.

A compression spring 34 surrounds the rod 33 and is disposed between thepivoted end of the rod and the yoke 17 The urpose of the spring 34 is tomove the clutc yoke 17, the shaft 12 and the switch 11 to open or closedpositions with a snap action, in re-.

sponse to a predetermined movement of the The movement of the plate 8,and the movement of the shaft 12 and switch blade 11 is limited by thearm 37 fixed to the shaft 12 and operating between stop members 38 and39 on a stop plate 41 secured to the frame 8.

As shown in Figs. 1 and 2, the switch member is in closed position andis rotated in a clockwise direction to open position, as indicated bythe arrow in Fig. 1. To open the circuit breaker, the handle 16 is firstturned counter-clockwise, thus moving the pin 32 beyond the lineintersecting the plane of the longitudinal portion of the yoke 17 andthe axis of the switch shaft 12, at which time the compression spring 34causes the clutch yoke 17 to rotate clockwise and open the switch with asnap action. The opening 20 in the handle 16 is of sufiicient length topermit of the necessary relative movement between the handle and theclutch yoke.

To close the switch, the operating handle is turned in a clockwisedirection and the instant the shaft 32 passes beyond the line previouslyreferred to, the switch is moved to the closed position by means of thecompression spring 34. During the closing movement of the switch, thespring 15, which is weaker than the spring 34, is re-wound, so that itnormally tends to bias the switch towards open position.

Under severe overload or short-circuit conditions, the armature 29 isdrawn toward the electromagnet core, thus moving the clutch collars 22aand 25 outwardly and with drawing the clutch pins 22 from engagementwith the yoke end 18. The shaft 12 is then free to rotate with respectto the clutch yoke 17, and the spring 15 forces the switch to openposition with a snap action. If the shortcircuit or overload conditionsprevail until an attempt is made to re-close the circuit breaker, theclutch will be held out of o erative position, and it will'not be ossibe to move the switch member to closed position. If, however, ashort-circuit or overload occurs while the operating handle is in thehands of the operator, the circuit breaker will open, regardless of theposition of the operating handle. The circuit breaker is, therefore,trip-free of the handle.

The clutch collars 22a and 25 are yieldingly held in the closedoperative position with respect to the clutch oke by means of acompression spring 42 wliich surrounds an adjusting rod 24 that isdisposed in a recess 43 and engages an enlarged end 44 of the adjustingrod. The spring 42 normally tends to yieldingly retain the clutch pins22 in operative engagement with the clutch yoke. The clutch collars 22aand 25 may be adjusted longitudinally of the rod 24 and thus vary theforce required to cause release of the clutch. The mechanism may,therefore, be calibrated to cause the circuit breaker to open at anyredetermined current condition.

A therma element, such as a bi-metal strip or disc heated by currentconducted therethrough or b an associated heater connected in series witthe switch terminals, may be substituted for the electro-magnet.

A cover plate 45 is detachably mounted on the casing 7 and is providedwith a slot 46 through which the operating handle 16 extends to renderthe switch manually operable from the exterior of the housing. The slot46 is closed by an arcuate sealing plate 47 attached to the handle 16.

\Vhile I have illustrated but one embodi ment of my invention, it willbe apparent to those skilled in the art, that various changes,modifications, substitutions, additions and omissions may be made in theapparatus illustrated without departing from the spirit and scope of myinvention, as set forth in the appended claims.

I claim as my invention 1. A circuit breaker comprising a movablecontact member, means normally biasing the contact member toward openposition, an operating device including an overcenter spring andreleasably connected to the said contact member for moving the contactmember to open position and to closed position against the action ofsaid biasing means and. current responsive means for disconnecting theoperating device from the contact member for permitting the said biasingmeans to move the contact member to open position.

2. A circuit breaker comprising a movable contact member, means normallybiasing the contact member toward open posit-ion, an operating meansincluding an over-center spring llt releasably connected to the saidcontact mem ber for moving the contact member to open position and toclosed position against the action of said biasing means and foryieldingly retaining the contact member in either open or closedposition.

3. A circuit breaker comprising a movable contact member, means normallybiasing the contact member toward open position, an operating meanshaving co-operating, relatively movable elements one of which isreleasably connected to the said contact member and the other of whichis manually operable for moving the first said element when the secondsaid element is moved a predetermined distance, means for yieldinglyretaining the said elements in extreme positions of movement, andcurrent responsive means for dis connecting the first said element fromthe contact member.

4. A circuit breaker comprising a contact member, a switch membermovable into and out of engagement with the contact member, a springnormally biasing the switch member into open position out of engagementwith the contact member, a clutch means releasably connected to theswitch member, an operating member, a spring connecting the operatingmember with the clutch member for moving the switch member into or outof engagement with the contact member in response to a predeterminedmovement of the operating member, and current responsive means forreleasing the clutch member to permit the switch to be moved to openposition by the first said spring in response to predetermined currentconditions.

5. A circuit breaker comprising an oseillating switch member, a clutchmeans releasably connected thereto, an operating member, an overcenterspring connecting the clutch means and the operating member for movingthe switch member to open and closed positions with a snap action inresponse to a predetermined movement of the operating member, a springnormally biasing the switch member to open position and adapted to bere-wound when the switch is moved to closed position, and currentresponsive means for releasing the switch member from the clutch meansfor permitting the last said spring to move the switch member to openposition in response to predetermined current conditions.

6. A circuit breaker comprising a switch member movable to open andclosed positions, a shaft for the switch member, a support for theshaft, a spring attached at one end to the support and at the other endto the shaft for normally biasing the switch toward open position andadapted to be rewound when the switch is moved to closed position. aclutch member 1 tatably mounted on the shaft and rclcasably securedthereto, an operating member rotatably mounted on the shaft, a springconnecting the, operating member to the clutch member for moving theswitch member to open and closed positions with a snap action inresponse to a predetermined movement of the operating member and to thecurrent responsive means for releasing the clutch member to permitopening movement of the switch by the first said spring in response topredetermined current conditions.

7. A circuit breaker comprising a contact member a switch member movableinto and out of engagement with the contact member, a spring movablybiasing the switch member into open position and out of engagement withthe contact member, a clutch means releasably connected to the switchmember, an operating member, a spring connecting the operating memberwith the clutch member for moving the switch member into and out ofengagement with the contact member in re sponse to a predeterminedmovement of the operating member. current responsive means for releasingthe clutch means to permit the switch to be moved to open position bythe first said spring in response to predetermined current conditions,and adjustable means for controlling operation of the clutch means.

8. A circuit breaker comprising a switch member movable to open andclosed positions, a hollow shaft for the switch member, a support forthe shaft, a spring for normally biasing the switch toward open positionand adapted to be re-wound when the switch is moved to closed position.a clutch member rotatably mounted on the shaft and releasably securedthereto, an operating member rotatably mounted on the shaft. a springconnecting the operating member to the clutch member for moving theswitch member to open and closed positions with a snap action inresponse to a predetermined movement of the operating member. a currentresponsive means for releasing the clutch member to permit openingmovement of the switch by the first said spring in response topredetermined current conditions. an adjusting rod extending through thesaid shaft and connected to the clutch means. and a tcnsioning springmounted on the rod for controlling the operation of the said clutchmeans.

In testimony whereof. T have hereunto subscribed my name this l l-th dayof l eln-uary,

CLARENCE D. BURROWVS.

